Pathogenesis of Neurodegenerative Diseases Caused by Mutations in Senataxin

描述（由申请人提供）：本提案的目的是了解Sen 1解旋酶在终止RNA聚合酶II（PolII）转录物中的作用，并确定Sen 1人类同源物Senataxin（SETX）突变如何导致神经退行性疾病2型共济失调-眼神经麻痹-失用症（AOA 2）和4型肌萎缩性侧索硬化症（ALS 4）。 基于酵母模型，我们提出SETX突变通过破坏转录终止引起人类疾病。 因此，我们希望确定确切的功能的Sen 1/SETX解旋酶在转录终止和这些功能在疾病中被破坏的方式。 该补助金的第一个目的是更多地了解酵母Sen 1在转录终止中的作用及其受转录终止机制其他组分的调节。 我们将确定是否Sen 1终止PolII通过直接行动，或间接通过其对小核仁核糖核蛋白（snoRNP）组装的影响。 我们将通过在次优细胞Sen 1水平下分析snoRNP颗粒的蛋白质和RNA组成来实现这一点。 接下来，我们将确定由Sen 1突变引起的细胞死亡的机制。 这将通过减轻snoRNA信息阅读到下游必需基因中的启动子封闭效应来实现。 如果目前接受的假设是正确的，这应该抑制与Sen 1丢失相关的致死性。 随后，我们将探讨磷酸化在Sen 1调控中的作用。 第二个目的是确定酵母Sen 1和人SETX功能的共同特征。 我们将亲和纯化SETX并鉴定与之相关的蛋白质和转录物，我们还将探索这些相关性是如何被磷酸化调节的。 第三个目标是确定人类SETX突变导致疾病的机制。 我们将定义SETX中的突变如何改变其蛋白质和RNA结合特性，并检查与SETX相关的蛋白质中的突变是否会导致与SETX中的突变类似的细胞代谢缺陷。 我们相信，上述目标的实现将导致更好地了解转录终止的调控和神经退行性疾病的发病机制。 获得的关于SETX功能的信息可能使我们能够设计新的策略来逆转神经退行性疾病如ALS 4和AOA 2的进展。 我们的工作将研究Senataxin蛋白（SETX）的突变如何导致神经退行性疾病共济失调眼失用症2型（AOA 2）和肌萎缩侧索硬化症4型（ALS 4）。 所获得的知识可能会提供新的策略来逆转神经退行性疾病的进展。

DESCRIPTION (provided by applicant): The goal of this proposal is to understand the role of the Sen1 helicase in termination of RNA Polymerase II (PolII) transcripts and to establish how mutations in the human homolog of Sen1, Senataxin (SETX), cause the neurodegenerative disorders Ataxia-Oculomotor-Apraxia type 2 (AOA2) and Amyotrophic Lateral Sclerosis Type 4 (ALS4). Based on the yeast model, we propose that SETX mutations cause human disease through disruption of transcriptional termination. Thus, we want to define the precise function of the Sen1/SETX helicases in transcriptional termination and the manner in which these functions are disrupted in disease. The first aim of the grant is to learn more about the role of yeast Sen1 in transcription termination and its regulation by other components of the transcription termination machinery. We will determine whether Sen1 terminates PolII by direct action, or indirectly via its effect on small nucleolar ribonucleoprotein (snoRNP) assembly. We will accomplish this via analysis of the protein and RNA composition of the snoRNP particles under suboptimal cellular Sen1 levels. Next, we will identify the mechanism of the cell death caused by mutations of Sen1. This will be accomplished through alleviating the promoter occlusion effect of snoRNA messages reading into downstream essential genes. If the currently accepted hypothesis is correct, this should suppress the lethality associated with Sen1 loss. Subsequently we will explore the role of phosphorylation in the regulation of Sen1. The second aim is to identify the shared characteristics of yeast Sen1 and human SETX function. We will affinity purify SETX and identify the proteins and transcripts that associate with it. We will also explore how these associations are regulated by phosphorylation. The third aim is to identify the mechanism by which mutations in human SETX cause disease. We will define how mutations in SETX change its protein and RNA binding properties and examine whether mutations in proteins that SETX associates with cause similar defects in cellular metabolism as mutations in SETX. We believe that accomplishment of the goals outlined above will lead to a better understanding of the regulation of transcriptional termination and the pathogenesis of neurodegenerative disorders. The information obtained about the function of SETX might allow us to devise new strategies to reverse the progression of neurodegenerative diseases like ALS4 and AOA2. Project Narrative Our work will investigate how mutations in the Senataxin protein, SETX, cause the neurodegenerative disorders Ataxia Oculomotor Apraxia type 2 (AOA2) and Amyotrophic Lateral Sclerosis Type 4 (ALS4). The knowledge gained might provide new strategies to reverse the progression of neurodegenerative diseases.